/Engine/Source/Runtime/Slate/Public/Framework/Layout/ScrollyZoomy.h
Should be called from your widget's OnMouseLeave override.
void OnMouseLeave ( const [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< [SWidget](API\Runtime\SlateCore\Widgets\SWidget) > MyWidget, const [FPointerEvent](API\Runtime\SlateCore\Input\FPointerEvent) & MouseEvent )